端口：卡片之间的通信

const delivered = await card.ports.emit('failures', [
  { text: 'checkout › pays with a saved card', status: 'error' },
  { text: 'auth › logs in with SSO', status: 'error' }
])
if (delivered === 0) card.ui.toast('Connect me to a todo list to track these')

await card.ports.send(noteId, 'summary', '## Nightly run\n\nAll green.', { input: 'replace' })

card.ports.onMessage<string>((text, message) => {
  render(`${message.fromKind} card ${message.from} sent ${message.type} on ${message.output}`, text)
}, { input: 'notes' })

{ "id": "lookup", "label": "Look up", "type": "ns:text", "mode": "request",
  "response": { "type": "ns:json" } }

// The answering card:
card.ports.onRequest<string>('lookup', async (query, request) => {
  const hits = await search(query, request.signal)   // request.signal aborts at the deadline
  return { query, hits }                               // checked against response.type
})
 
// The asking card (connected to it by an arrow, either direction):
const answer = await card.ports.request<{ hits: string[] }>(peerId, 'lookup', 'flaky tests', {
  timeoutMs: 10_000
})
render(answer.hits)
 
declare function search(q: string, signal: AbortSignal): Promise<string[]>
declare const peerId: string

const last = await card.ports.read<{ text: string }[]>(todoId, 'items')
if (last) render(`${last.data.length} items, as of ${new Date(last.at).toLocaleTimeString()}`)
 
declare const todoId: string

import type { PeerInfo } from '@neurosquad/card-sdk'
 
function describePeer(peer: PeerInfo): string {
  const ins = peer.inputs.map((p) => `${p.id}:${p.type}`).join(', ') || 'none'
  const outs = peer.outputs.map((p) => `${p.id}:${p.type}`).join(', ') || 'none'
  return `${peer.name} (${peer.kind}, ${peer.direction}) — in: ${ins}; out: ${outs}`
}
 
card.ports.peers.forEach((peer) => render(describePeer(peer)))
card.ports.onPeersChanged((peers) => render(peers.map(describePeer)))
 
// Is there a checklist downstream that takes tasks?
const taskSink = card.ports.peers.find(
  (p) => p.direction !== 'upstream' && p.inputs.some((i) => i.type === 'ns:tasks')
)
render(taskSink?.name ?? 'no task list connected')

import { hasDownstreamPeer, permissionForPeer, requestPermissions } from '@neurosquad/card-sdk'
 
async function sendSummary(text: string): Promise<void> {
  if (!hasDownstreamPeer(card.ports.peers)) {
    card.ui.toast('Draw an arrow from this card to a note')
    return
  }
  // Which permission does sending Markdown to each peer need? (cards.connected for a note)
  const needed = card.ports.peers
    .map((peer) => permissionForPeer(peer, { outputType: 'ns:markdown' }))
    .filter((id) => id !== null)
  // Asks only for what is missing; never throws — resolves with what is usable now.
  const usable = await requestPermissions(card, ...needed)
  if (usable.length === needed.length) await card.ports.emit('summary', text)
}